I have no documents with my Cruiser 89 but I checked with DVLA as the reg number doesn't appear when you search for it on their website. They said they have a partial record for the number and I should be able to get it back but I need to fill in form V55/5 - 'Application for first vehicle tax and registration of a used vehicle'. I have filled it in but can only answer about 30% of the questions (the form is used for imported vehicles also as well as many other types). It is so vague that I'm not even sure if I have to pay but I don't think so (exclusions include 'historic vehicles previously registered with the old local authorities (late conversions)'). Now that I don't need an MOT it should be really simple but does this sound like the correct form?, and can I leave more than half of it blank?

If it comes back with 'Vehicle details could not be found' then its still worth sending them an enquiry as my number is known to them even though it came up as 'not found'. I assume this is because it has never had a V5(C) issued but was entered on the computer back in 1983 when they changed over.

If you don't know the original number then it's almost impossible unless you know the location place of the first registration and from the year of the bike you can trawl through the local records office hoping to find your frame number on an index card , or less likely in the number allocation books. Of course not all records survived. The Kithead Trust have a list of which do and where they are.